This story is a supplement to the feature "So You Think You Can Dance?: PET Scans Reveal Your Brain's Inner Choreography" which was printed in the July 2008 issue of Scientific American.
To identify brain areas important to dance, the authors had amateur tango dancers lie flat inside a PET scanner. The device held their heads stationary, but they were able to listen to tango music through headphones and move their legs along an inclined surface (below).
In one such experiment, the machine scanned the brain under two different conditions: when the dancers flexed their leg muscles in time to the music but did not move their limbs and when the subjects performed a basic tango box step (inset) with their legs, again in time to the music. When the authors subtracted brain activity caused by muscle contraction (top scan) from the tango scans, what remained “lit” was a part of the parietal lobe known as the precuneus (bottom scan).